wrenches

Wrenches are hand tools designed to apply torque to rotate fasteners such as nuts and bolts. They provide grip and mechanical advantage, allowing users to loosen or tighten fasteners that would be difficult to move with bare hands. Wrenches vary widely in shape, size, and mechanism, and they are essential in mechanical, automotive, construction, and maintenance work.

Common types include open-end wrenches, which have two open jaws; box-end wrenches, which enclose the fastener heads; and combination wrenches, which combine both forms on opposite ends. Adjustable wrenches have a movable jaw to fit multiple sizes. Socket wrenches use a ratchet handle with interchangeable sockets to reach fasteners in tighter spaces. Torque wrenches are designed to apply a specific torque value. Pipe wrenches grip round or cylindrical objects with adjustable jaws for plumbing tasks. Hex keys (Allen wrenches) are L-shaped wrenches that drive hex socket screws. Other specialized wrenches include flare-nut, Torx, and spline variants for specific fasteners.

Sizes and standards vary by region. Wrenches are described by the distance across the flats of the fastener they fit, measured in inches (SAE) or millimeters (metric). ISO, DIN, and JIS standards define many common sizes and tooth or jaw geometries. Materials are typically high-strength alloy steels such as chrome-vanadium or chrome-plated steel to resist wear and corrosion.

Usage and safety emphasize selecting the correct size, applying force in line with the handle, and avoiding overtightening or bending. Regular inspection and proper lubrication extend tool life.